One of the earliest radio navigation systems was Radio Direction Finding (RDF). Introduced in the 1920s, RDF allowed pilots to determine the direction of a ground-based radio transmitter.

Using digital techniques has caused a resurgence of interest in VLF — very low frequency — radio. Thanks to software-defined radio, you no longer need huge coils. However, you still need a suitable ...

The Pentagon wants more accurate high-frequency direction-finding antenna for small aircraft. Credit: U.S. Army The Defense Innovation Unit is looking to find a prototype small high-frequency ...

SAN ANTONIO -- Nov. 19, 2019 -- Mitigating ongoing threats to national security requires timely intelligence data, including signals intelligence (SIGINT) obtained through electronic surveillance.